Negative Energy Summon
To use negative energy, you need to learn how to summon it first. Feel out the ki in your body. Now begin to think of feelings that strongly anger you. Also think of things of evil(demons, vampires, etc...). Now picture all those thoughts spreading out of your mind and creating a coat around your body. Now use the ki flame power up so that your ki has to pass through the coating. As it does, picture the coating changing the color of your ki to a dark purple or blue, an
Make a ki ball in a darkened room. Absorb the dark energy in the room. Visualize it like the ki ball is attracting the dark ki. Then make a ki ball with that energy.
The Ghostly Scream: By Akuma Serge(i think)
Power all of your dark energy into your palm. Focus all of your hatred into a ki ball. Finally scream and shoot it out.
Maken Doku Ha
Draw energy from something dark and let the lunar ki flow throughout your body for a while. After you get used to having a lot of dark energy in you, move the dark ki into your hands. The fire it like a kamehameha while you yell.
First take all of your energy and convert it into darkness, if you dont have energy then you should draw mana from the darkness. Then Lift your hands over your head and pull all the darkness energy into your hands. You should do this until it is feeling very heavy. Then make it unstable by making it to where it will explode on contact. To do this simply imagine it like a bomb. Then throw it hard against a target or down on the ground. It will hurt you and everything else in its way.
Grab someone and visualize roots from your palms attaching to the person's body. Visualize the roots sucking the energy/ki from them. Also, this takes practice so it probably wont work first time.